The present invention relates to an electrical connector comprising a jack which has incorporated therein a movable contact piece so arranged that when a plug is inserted into the jack, the movable contact piece is connected with the plug and, at the same time, is disconnected from another contact piece in the jack, and when the plug is pulled out of the jack the movable contact piece in the jack recovers its original state.
Conventional jacks of this kind often become defective owing to deteriorated resiliency of the movable contact piece caused by repeated insertion and pulling out of the plug. In view of this, it has been proposed to interpose a coiled spring between the movable contact piece and a stationary part of the jack to supplement the resiliency of the movable contact piece, thereby to lengthen the lifetime of the jack. In this prior art jack, the coiled spring is not held firmly in place, and hence is likely to get out of position while in use. Furthermore, conventional jacks, in particular small ones, have the defect that, when assembling them, it is difficult to hold the coiled spring in position.
Moreover, there is the possibility in the prior art arrangement that when the plug inserted into the jack receives an external force across the axis of a plug insertion hole of the jack, the movable contact piece can be excessively displaced by the inserted end portion of the plug, and permanently deformed. To avoid this, there has been proposed a jack designed so that, when the movable contact piece is displaced to a predetermined extent, it is received by a protective member to prevent further displacement.